An Integrated Approach of Breeding and Maintaining an Elite Cultivar of Snap Bean

Abstract

This study is an attempt to describe a functional breeding and maintaining program of intraselection in a traditional snap bean ( Phaseolus vulgaris L.) cultivar. The program was applied in three stages. The first thing examined was the existing genetic variability of source material for earliness and pod yield potential. Single‐plant frequency distributions with positive skewness for earliness showed that the frequency of unfavorable alleles was high. For total pod yield, distribution was found normal. Thus, the end‐target should be selection for early maturity, keeping, and stabilizing high yield. The seed shape uniformity was added as third criterion of selection. Secondly, combined pedigree intraselection, based on widely spaced single‐plant performance, for the prementioned traits was applied for three successive generations. The evaluation of the third‐generation families revealed progenies with high yield, earliness, and stability of performance. Thirdly, the end‐product of the program applied was to restore or even improve the cultivar. The evaluation of improved selections of fourth‐generation families and of the source material, at dense stand, showed that all families were the only ones producing high and stable early fresh pod harvest, even 53 d after planting (53.25–80 g/plant, compared with 0 g/plant of the control). The total pod yield of all the families was 219 to 276% superior compared with source material. Conclusively, the widely spaced single‐plant combined pedigree intraselection was proved reliable and effective in restoring or even improving the local cultivar of snap bean according to update demands.